No chips. Get your PCM reprogammed by one of the vendors here, pcmperformance.com or pcmforless. Do some reading here and learn about your car for starters and develop a plan before your start modding. Good luck.
You have a reprogrammable pcm not a removable chip. The only thing nside the coer on the pcm you can remove is the knock module. Dont' do it. Buy a cable and tunercat, send it out or order a tuned exchange one from pcmforless, trifecta, or pcmperformance. There are others, those are just the ones i can remember right now.
There is no such thing as a chip for these cars. They use programming that is written into the PCM.
If you're looking to have it programmed for economy or power or any modifications you can't go wrong with Alex from PCMerformance. In fact he is having a sale on programming right now to forum members. Check this out: http://www.impalassforum.com/vBulletin/showthread.php?t=234721 Check out his web site or give him a call. Run a search on the forum you will find nothing but praise for his work. I have tried most of the programers and can honestly say Alex has been the best.